Thanks for the interesting bit on bullets fired from land to water. A final question - can the underwater pistols be fired from above water and does the act of entering the water -straight in or at an angle-impede their effectiveness?
Link to staff report: http://www.straightdope.com/mailbag/mgununderwater.htm
There’s nothing to prevent the SPP-1 from firing above water, but the lack of rifling will hurt the projectile’s stability through the air. Over a short distance to the water, it probably would not be… er… fatal to the projectile’s effectiveness, but the farther away you got and the greater angle variance from a flight path perpendicular to the plane of the water, the more effectiveness you’ll lose. At some critical angle, the water will cause a riccochet of the projectile. As long as the angle of attack is less than that critical angle, the projectile will enter the water, and, yes, entering the water will also degrade its effectiveness.
Quantifying any of those general statements with some sort of mathematical model might be problematic, which is why the Mythbusters team built themselves a water tank.
The article does not mention the Gyrojet, a 60s gun that fired bullet-sized miniature rockets. (There were multiple exhaust ports at an angle, to provide spin.) It was relatively usable under water. It ultimately failed as a weapon because it was too inaccurate for anything but self defense, while it had no stopping power at short range, making it inadequate for that, too. But the men from U.N.C.L.E. employed it on one mission…
Nitpick: the Mythbusters team used a M1 Garand, not a M1 Carbine. I just watched the episode to confirm this. The difference is significant in this case, since the carbine uses a less powerful .30 carbine round, while the Garand uses the .30-06 . In this case, actually, the carbine might have performed better than the Garand, since the high-energy rifle bullets all shattered when they hit the water, while the smaller pistol rounds (which are similar to the .30 carbine round) penetrated further underwater.
Right you are – my own Mythbusters cite says it was a Garand, and I must have used my own (obviously flawed) memory of the episode in substituting a phantom Carbine.
Well, before you go crazy, if your reference was the Annotated Mythbusters site, I posted the same nitpick there and they just changed it. It also originally referenced the carbine instead of the Garand.
The Phantom Carbine
…naw.
Oh, thank goodness. I was just about to sign the voluntary committal forms for Trembling Oaks Rest Home.
I’ve a hunch that, at angles of incidence significantly closer to perpendicular than the riccochet critical angle, something akin to Snell’s Law (which governs refraction of light through various slower-than-vacuum media) would apply. This would not, however, apply to riccochet, nor probably situations close to riccochet, since the analogous situation for light or other waves occurs when the wave is originating in the slower medium, not the faster one. This might be because the water imposes an acceleration on the bullet, not an absolute speed limit. Alternately, it might be the sound speed in the two media which is relevant, not the projectile speed. A specialist in fluid dynamics could probably say more.
The interesting thing is that the Mythbusters episode tested the bullet-into-water effectiveness using FMJ ammunition.
I can tell you that Soft Point of JHP bullets have an effective range of only a few inches in water- a 180gr SP .303 British round fired into a river will not kill a fish 6 inches below the surface, for example.*
*Discharging firearms into water is a dangerous practice and should never be attempted outside of a controlled environment, by trained/knowledgeable professionals, with all appropriate safety precautions taken.
“What if they’ve got a pointed stick… underwater?” - Mr. Harrison
“SHUT UP!” - Drill Sergeant
Unless, of course, you live in Vermont. :eek:
Some time back I asked a GQ about lethality when firing into water, being familiar with ballistic testing of bullets fired into a water box versus the scene in “Saving Private Ryan” of bullets still moving at a lethal velocity after traveling several feet through water. I’m thankful that Mythbusters answered some of my questions and that Bricker relayed the answers so well without me needing to get cable, though I still regret he’s not a hot, redheaded woman. (“Still regret” because I’ve long felt I’d be more inclined to pretend to agree with him if he were a hot, redheaded woman.)
This was another very good report Bricker, well done.
Jim
Has anyone tried it with a solid bullet, like the ones used for dangerous game?
There’s lots of folks I regret aren’t hot, redheaded women. Indeed, I would venture to say that the world would be a much better place if everyone [sub]except me[/sub] were a hot, redheaded woman. Bonus points if a significant fraction of them were hot, redheaded, nerdy women.
Another nitpick similar to the above:
The .223 rifle used in the episode was NOT a hunting rifle. It was an AR-15 the civilian variant of the military M-16. While it could be used for hunting some areas restrict the use of anything considered an assault rifle while hunting. Also most areas allow you to carry no more than 5 rounds in the weapon while hunting (Some even state that your rifle must have an internal box magazine if it holds more than 1 round) and it would be a real hassle to show your 5 rounds to every game warden that questioned you while carrying your AR-15 with 20 or 30 round magazines.
That’s a bit too nit-picky for me to make a correction. The .223 is a well-known hunting round, and I don’t believe the performance in the test would have been significantly different if it had been delivered by a Ruger M77.
Got to ask, where is it a well known hunting round? And what are you hunting? As a deer round it is woefully inadequate. Hit a squirell and you wonder whet it went, so you do not that. Anyone considering the 5.56 AKA .223 a hunting round is eighter not a hunter or a person who needs a hunter class.
that will teach me to type mad without spell checking before sending!